02 Viper over rev and clutching

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02ViperMtn

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Joined
Jan 4, 2009
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166
Age
48
Location
Kamloops, BC
I have a slight over rev problem. This is my setup to the best i can determine.

02 SX Viper that has been modified to be a mountain viper. 151 track, bender triple pipes, mountain gearing/jetting/clutching.

The last 2 years the sled would rev to 9000 and then settle down to about 8800-8900RPM on a hill climb. At lower elevaions it would tend to rev a bit higher, but i was never on it hard until I was up in the peaks so I wasn't too concerned.

This year i installed a brand new OEM 8dn belt and I am reving to 9200 at WOT and can feel a loss of power past 8500RPM. Clutching is primary G-W-G with 8ek weights and rivets as shown in attached picture. Rollers are 14.5mm. Secondary is a black spring with 90deg wrap (6 and 3). I cannot find a marking on it at all. I am guessing it may be a green. How can I take it off too confirm? Helix is 47.

Is my new belt slipping? I can see a bit of black on one spot high on the primary as shown in pic. I will wash the clutches and belt next. Should I try decreasing wrap to 80deg? Should I try more weight in the primary? Should I try a different clutching setup entirely and try to increase performance in deep snow and mountains or is this setup on the right track? I like how it ran the last 2 years, i would be fine just dropping the RPM to around 8700.

New setup or just drop the rpms to 8700 and how? Suggestions or ideas please?
 

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i see no pic of the rivets. also, i would go back to the y/w/y spring. as for a black secondary spring, they are all painted black, but have a little dot of paint on one of the coils and that dot will be of a certain color.....red, green, silver, etc. what helix do you have in there. also, if you have springs in holes 6-2, your at 80deg and not 90deg.

what size rollers do you have in the primary?
 
Thanks for pointing out a mistake. My wrap is 90deg (6 and 3). My helix is 47deg (just added that). And i have just added the pictures.

How easy is it to remove the helix on the sled so i can confirm my secondary. How do I do it.

Thanks all.
 
im not a clutching guru but did you clean the belt and clutches before install? and if you did wrap the secondary 3&3 and see if that helps it should hope this helps
 
clean your new belt every time you buy one, clean your clutches as often as possible. yeah try secondary at 70 first if need be go to 3&3 the stock rpm i think is alittle higher than an srx it does seem like your over reving even last year but that could of been from your old belt.
 
i have slp pipes my sweet spot is 8750 rpms i know other pipes were alittle higher but i think benders were around 8800 hauck and aeens 9000 if not mistaken. someone will chime in with correct ### i would hope do a search you will find proper rpmsfor your pipes.It was a big deal in 2002 at the time.
 
i'm not sure which rivets you have installed in the tip, but i would replace it w/one that's not drilled thru like that. also, what spring do you have in that secondary? what other primary springs do you have to try out? what other helixs do you have to try out too?
 
I pulled the secondary off and confirmed that the secondary is a straight black spring, no marking what so ever. It didn't seem worn enough in any locations that the paint mark could have been rubbed out. No idea who's spring this is. I cleaned everytinhg off and reassembled everything and changed the seconday wrap from 90 to 70, but didn't get a chance to ride it for testing. Do mountain sleds work well with varying degree helixs or not so much? I do not have any other springs or helixs to try at this time.
 
I wonder if you have a goodwin spring or something in there. I would find myself a green yamaha spring and start out at 70deg, try some new 3.6g rivets in the tip, a y/w/y spring, and maybe a 47 OEM helix, cause I believe you stated you have a 45 OEM?
 
The secondary may have come from Mountain Performance Inc. or Hartman, as this is where the previous owner got the tunnel ext and other parts when he modified it to be a mtn viper.

I think i may just get the yamaha green and take it with me next time i am out. I changed the wrap from 90 to 70 so i am wondering how much difference i may see on the back shift. I better be prepared to change it next time i ride.

How about the helix? Is it a good idea to go to a 53/47 multi angle helix for a mountain sled? Would i still use the yamaha green secondary? My helix now is 47, would i go with a multi that has the 47 as a second number as a place to start?
 
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02ViperMtn said:
The secondary may have come from Mountain Performance Inc. or Hartman, as this is where the previous owner got the tunnel ext and other parts when he modified it to be a mtn viper.

I think i may just get the yamaha green and take it with me next time i am out. I changed the wrap from 90 to 70 so i am wondering how much difference i may see on the back shift. I better be prepared to change it next time i ride.

How about the helix? Is it a good idea to go to a 53/47 multi angle helix for a mountain sled? Would i still use the yamaha green secondary? My helix now is 47, would i go with a multi that has the 47 as a second number as a place to start?
Click to expand...

i would think a 53/47 would be too steep in a mountain application. i would leave the stock 47 in there and see how it works. maybe you have a silver yamaha spring in there now?
 
there is one spot on the spring that appears rubbed silver from the helix, or it could possibly be remanants of a yamaha silver. What effect would going to a green on the secondary from a silver have if indeed it is a silver? I just talked to Mountain performance and they suggested a 48/42 helix if i were to try multi angle. Any thoughs on that helix?

Thanks again for all the help.
 
doesn't sound like a bad angle to try out. could very well be the remains of silver paint on that spring like you thought. the green spring isn't as stiff, so the rpms will drop alittle, from it not holding the secondary back from shifting as much.
 
i think i will try these spring and helix changes for fun. This may result in having to change the front weights though???? Hopefully i wouldn't need to buy new weights entirely.
 
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